Method and apparatus for detecting moisture in building materials

ABSTRACT

A moisture sensor system is described. In one embodiment, the provides an adjustable threshold level for the sensed moisture level. The adjustable threshold allows the moisture sensor to adjust to ambient conditions, aging of components, and other operational variations while still providing a relatively sensitive detection capability. In one embodiment, the adjustable threshold moisture sensor is used in an intelligent sensor system that includes one or more intelligent sensor units and a base unit that can communicate with the moisture sensor units. When one or more of the moisture sensor units detects a excess moisture the moisture sensor unit communicates with the base unit and provides data regarding the moisture condition. The base unit can contact a supervisor or other responsible person by a plurality of techniques, such as, telephone, pager, cellular telephone, Internet (and/or local area network), etc. In one embodiment, one or more wireless repeaters are used between the moisture sensor units and the base unit to extend the range of the system and to allow the base unit to communicate with a larger number of sensors.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No.11/562,352, filed Nov. 21, 2006, titled “METHOD AND APPARATUS FORDETECTING MOISTURE IN BUILDING MATERIALS,” which is a continuation ofapplication Ser. No. 11/233,931, filed Sep. 23, 2005, titled “METHOD ANDAPPARATUS FOR DETECTING MOISTURE IN BUILDING MATERIALS,” now U.S. Pat.No. 7,142,123, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sensor system for detecting anddetermining the severity of moisture in building materials, such aswood, drywall, plaster, etc.

2. Description of the Related Art

Maintaining and protecting a building or complex is difficult andcostly. Some conditions, such as fires, gas leaks, etc., are a danger tothe occupants and the structure. Other malfunctions, such as moisture inroofs, plumbing, walls, etc., are not necessarily dangerous for theoccupants, but can, nevertheless, cause considerable damage. In manycases, an adverse ambient condition such as water leakage, fire, etc.,is not detected in the early stages when the damage and/or danger isrelatively small. Sensors can be used to detect such adverse ambientconditions, but sensors present their own set of problems. For example,adding sensors, such as, for example, smoke detectors, water sensors,and the like in an existing structure can be prohibitively expensive dueto the cost of installing wiring between the remote sensors and acentralized monitoring device used to monitor the sensors. Adding wiringto provide power to the sensors further increases the cost.

SUMMARY

The present invention solves these and other problems by providing arelatively low cost, robust, wireless sensor system that provides anextended period of operability without maintenance. The system includesone or more intelligent sensor units and a base unit that cancommunicate with the sensor units. When one or more of the sensor unitsdetects an anomalous condition (e.g., moisture, smoke, fire, water,etc.) the sensor unit communicates with the base unit and provides dataregarding the anomalous condition. The base unit can contact asupervisor or other responsible person by a plurality of techniques,such as, telephone, pager, cellular telephone, Internet (and/or localarea network), etc. In one embodiment, one or more wireless repeatersare used between the sensor units and the base unit to extend the rangeof the system and to allow the base unit to communicate with a largernumber of sensors.

In one embodiment, the sensor system includes a number of sensor unitslocated throughout a building that sense conditions and report anomalousresults back to a central reporting station. The sensor units measureconditions that might indicate a fire, water leak, etc. The sensor unitsreport the measured data to the base unit whenever the sensor unitdetermines that the measured data is sufficiently anomalous to bereported. The base unit can notify a responsible person, such as, forexample, a building manager, building owner, private security service,etc. In one embodiment, the sensor units do not send an alarm signal tothe central location. Rather, the sensors send quantitative measureddata (e.g., smoke density, temperature rate of rise, etc.) to thecentral reporting station.

In one embodiment, the sensor unit is placed in a building, apartment,office, residence, etc. In order to conserve battery power, the sensoris normally placed in a low-power mode. In one embodiment, while in lowpower mode, the sensor unit takes regular sensor readings and evaluatesthe readings to determine if an anomalous condition exists. If ananomalous condition is detected, then the sensor unit “wakes up” andbegins communicating with the base unit or with a repeater. Atprogrammed intervals, the sensor also “wakes up” and sends statusinformation to the base unit (or repeater) and then listens for commandsfor a period of time.

In one embodiment, the sensor unit is bi-directional and configured toreceive instructions from the central reporting station (or repeater).Thus, for example, the central reporting station can instruct the sensorto: perform additional measurements; go to a standby mode; wake up;report battery status; change wake-up interval; run self-diagnostics andreport results; etc. In one embodiment, the sensor unit also includes atamper switch. When tampering with the sensor is detected, the sensorreports such tampering to the base unit. In one embodiment, the sensorreports its general health and status to the central reporting stationon a regular basis (e.g., results of self-diagnostics, battery health,etc.).

In one embodiment, the sensor unit provides two wake-up modes, a firstwake-up mode for taking measurements (and reporting such measurements ifdeemed necessary), and a second wake-up mode for listening for commandsfrom the central reporting station. The two wake-up modes, orcombinations thereof, can occur at different intervals.

In one embodiment, the sensor units use spread-spectrum techniques tocommunicate with the base unit and/or the repeater units. In oneembodiment, the sensor units use frequency-hopping spread-spectrum. Inone embodiment, each sensor unit has an Identification code (ID) and thesensor units attaches its ID to outgoing communication packets. In oneembodiment, when receiving wireless data, each sensor unit ignores datathat is addressed to other sensor units.

The repeater unit is configured to relay communications traffic betweena number of sensor units and the base unit. The repeater units typicallyoperate in an environment with several other repeater units and thus,each repeater unit contains a database (e.g., a lookup table) of sensorIDs. During normal operation, the repeater only communicates withdesignated wireless sensor units whose IDs appears in the repeater'sdatabase. In one embodiment, the repeater is battery-operated andconserves power by maintaining an internal schedule of when it'sdesignated sensors are expected to transmit and going to a low-powermode when none of its designated sensor units is scheduled to transmit.In one embodiment, the repeater uses spread-spectrum to communicate withthe base unit and the sensor units. In one embodiment, the repeater usesfrequency-hopping spread-spectrum to communicate with the base unit andthe sensor units. In one embodiment, each repeater unit has an ID andthe repeater unit attaches its ID to outgoing communication packets thatoriginate in the repeater unit. In one embodiment, each repeater unitignores data that is addressed to other repeater units or to sensorunits not serviced by the repeater.

In one embodiment, the repeater is configured to provide bi-directionalcommunication between one or more sensors and a base unit. In oneembodiment, the repeater is configured to receive instructions from thecentral reporting station (or repeater). Thus, for example, the centralreporting station can instruct the repeater to: send commands to one ormore sensors; go to standby mode; “wake up”; report battery status;change wake-up interval; run self-diagnostics and report results; etc.

The base unit is configured to receive measured sensor data from anumber of sensor units. In one embodiment, the sensor information isrelayed through the repeater units. The base unit also sends commands tothe repeater units and/or sensor units. In one embodiment, the base unitincludes a diskless PC that runs off of a CD-ROM, flash memory, DVD, orother read-only device, etc. When the base unit receives data from awireless sensor indicating that there may be an emergency condition(e.g., a fire or excess smoke, temperature, water, flammable gas, etc.)the base unit will attempt to notify a responsible party (e.g., abuilding manager) by several communication channels (e.g., telephone,Internet, pager, cell phone, etc.). In one embodiment, the base unitsends instructions to place the wireless sensor in an alert mode(inhibiting the wireless sensor's low-power mode). In one embodiment,the base unit sends instructions to activate one or more additionalsensors near the first sensor.

In one embodiment, the base unit maintains a database of the health,battery status, signal strength, and current operating status of all ofthe sensor units and repeater units in the wireless sensor system. Inone embodiment, the base unit automatically performs routine maintenanceby sending commands to each sensor to run a self-diagnostic and reportthe results. The base unit collects such diagnostic results. In oneembodiment, the base unit sends instructions to each sensor telling thesensor how long to wait between “wakeup” intervals. In one embodiment,the base unit schedules different wakeup intervals to different sensorsbased on the sensor's health, battery health, location, etc. In oneembodiment, the base unit sends instructions to repeaters to routesensor information around a failed repeater.

In one embodiment, the sensor unit is configured to detect moisture inbuilding materials such as, for example, drywall, wood, plaster,concrete, etc. In one embodiment, two or more conductors are provided inproximity to the building material. The conductors are provided to asensor unit.

In one embodiment, a relatively low cost, robust, moisture sensor systemthat provides an adjustable threshold level for the sensed moisturelevel. The adjustable threshold allows the moisture sensor to adjust toambient conditions, aging of components, and other operationalvariations while still providing a relatively sensitive detectioncapability for hazardous conditions. The adjustable threshold moisturesensor can operate for an extended period of operability withoutmaintenance or recalibration. In one embodiment, the moisture sensor isself-calibrating and runs through a calibration sequence at startup orat periodic intervals. In one embodiment, the adjustable thresholdmoisture sensor is used in an intelligent sensor system that includesone or more intelligent sensor units and a base unit that cancommunicate with the moisture sensor units. When one or more of themoisture sensor units detects an anomalous condition (e.g., moisture,fire, water, etc.) the moisture sensor unit communicates with the baseunit and provides data regarding the anomalous condition. The base unitcan contact a supervisor or other responsible person by a plurality oftechniques, such as, telephone, pager, cellular telephone, Internet(and/or local area network), etc. In one embodiment, one or morewireless repeaters are used between the moisture sensor units and thebase unit to extend the range of the system and to allow the base unitto communicate with a larger number of sensors.

In one embodiment, the adjustable-threshold moisture sensor sets athreshold level according to an average value of the moisture sensorreading. In one embodiment, the average value is a relatively long-termaverage. In one embodiment, the average is a time-weighted averagewherein recent sensor readings used in the averaging process areweighted differently than less recent sensor readings. The average isused to set the threshold level. When the moisture sensor reading risesabove the threshold level, the moisture sensor indicates an alarmcondition. In one embodiment, the moisture sensor indicates an alarmcondition when the moisture sensor reading rises above the thresholdvalue for a specified period of time. In one embodiment, the moisturesensor indicates an alarm condition when a statistical number of sensorreadings (e.g., 3 of 2, 5 of 3, 10 of 7, etc.) are above the thresholdlevel. In one embodiment, the moisture sensor indicates various levelsof alarm (e.g., notice, alert, alarm) based on how far above thethreshold the moisture sensor reading has risen and/or how rapidly themoisture sensor reading has risen.

In one embodiment, the moisture sensor system includes a number ofsensor units located throughout a building that sense conditions andreport anomalous results back to a central reporting station. Themoisture sensor units measure conditions that might indicate a fire,water leak, etc. The moisture sensor units report the measured data tothe base unit whenever the moisture sensor unit determines that themeasured data is sufficiently anomalous to be reported. The base unitcan notify a responsible person such as, for example, a buildingmanager, building owner, private security service, etc. In oneembodiment, the moisture sensor units do not send an alarm signal to thecentral location. Rather, the moisture sensors send quantitativemeasured data (e.g., moisture, rate of rise, length of time, etc.) tothe central reporting station.

In one embodiment, the moisture sensor system includes abattery-operated sensor unit that detects moisture in buildingmaterials. The moisture sensor unit is placed in a building, apartment,office, residence, etc., and provided to a moisture probe. In order toconserve battery power, the moisture sensor is normally placed in alow-power mode. In one embodiment, while in the low-power mode, themoisture sensor unit takes regular sensor readings, adjusts thethreshold level, and evaluates the readings to determine if an anomalouscondition exists. If an anomalous condition is detected, then themoisture sensor unit “wakes up” and begins communicating with the baseunit or with a repeater. At programmed intervals, the moisture sensoralso “wakes up” and sends status information to the base unit (orrepeater) and then listens for commands for a period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sensor system that includes a plurality of sensor unitsthat communicate with a base unit through a number of repeater units.

FIG. 2 is a block diagram of a sensor unit.

FIG. 3 is a block diagram of a repeater unit.

FIG. 4 is a block diagram of the base unit.

FIG. 5 shows one embodiment of a network communication packet used bythe sensor units, repeater units, and the base unit.

FIG. 6 is a flowchart showing operation of a sensor unit that providesrelatively continuous monitoring.

FIG. 7 is a flowchart showing operation of a sensor unit that providesperiodic monitoring.

FIG. 8 shows a sensor system wherein relatively low-cost sensors providesensor readings and/or status information to an area monitor thatcommunicates with a base unit.

FIG. 9 shows a moisture sensor that includes an impedance sensorprovided to one or more impedance probes.

FIG. 10 shows the impedance sensor from FIG. 9 provided to an impedanceprobe configured as a pair of conductive strips.

FIG. 11 is a schematic of an impedance sensor configured to measureimpedance by using a voltage source and a current sensor.

FIG. 12 is a schematic of an impedance sensor configured to measureimpedance by using a current source and a voltage sensor.

FIG. 13 is a schematic of an impedance sensor configured to measureimpedance using a bridge.

FIG. 14 shows a moisture sensor that includes a time/frequency domainimpedance sensor provided to an impedance probe.

FIG. 15 is a plot showing an example output of the time-frequency domainimpedance sensor when a relatively small damp area is detected.

FIG. 16 is a plot showing an example output of the time-frequency domainimpedance sensor when a larger damp area is detected.

FIG. 17 is a schematic of one embodiment of a time-domain impedancesensor.

FIG. 18 is a rear view showing the impedance sensor provided to amolding.

FIG. 19 is a front view of the molding from FIG. 9 showing one methodconnecting the sensor unit 902 to the impedance probe.

FIG. 20 shows an impedance probe configured for peel-and-stickapplication to a molding.

FIG. 21 shows an impedance probe configured for peel-and-stickapplication to a wall or other building material.

FIG. 22 shows one installation of the moisture sensor unit to animpedance probe provided between a wall or ceiling and a molding,wherein the sensor unit is mounted to the wall (or ceiling).

FIG. 23 shows one installation of the moisture sensor unit to animpedance probe provided between a wall or ceiling and a molding,wherein the sensor unit is mounted to the molding.

FIG. 24 shows the impedance probes from FIG. 20 or 21 wrapped around acorner.

FIG. 25 shows the impedance probes from FIG. 20 or 21 overlapped tocover a longer area.

FIG. 26 shows a moisture sensor and a self-test sensor provided to amoisture probe.

DETAILED DESCRIPTION

FIG. 1 shows a sensor system 100 that includes a plurality of sensorunits 102-106 that communicate with a base unit 112 through a number ofrepeater units 110-111. The sensor units 102-106 are located throughouta building 101. Sensor units 102-104 communicate with the repeater 110.Sensor units 105-106 communicate with the repeater 111. The repeaters110-111 communicate with the base unit 112. The base unit 112communicates with a monitoring computer system 113 through a computernetwork connection such as, for example, Ethernet, wireless Ethernet,firewire port, Universal Serial Bus (USB) port, bluetooth, etc. Thecomputer system 113 contacts a building manager, maintenance service,alarm service, or other responsible personnel 120 using one or more ofseveral communication systems such as, for example, telephone 121, pager122, cellular telephone 123 (e.g., direct contact, voicemail, text,etc.), and/or through the Internet and/or local area network 124 (e.g.,through email, instant messaging, network communications, etc.). In oneembodiment, multiple base units 112 are provided to the monitoringcomputer 113. In one embodiment, the monitoring computer 113 is providedto more than one computer monitor, thus, allowing more data to bedisplayed than can conveniently be displayed on a single monitor. In oneembodiment, the monitoring computer 113 is provided to multiple monitorslocated in different locations, thus, allowing the data from themonitoring computer 113 to be displayed in multiple locations.

The sensor units 102-106 include sensors to measure conditions, such as,for example, smoke, temperature, moisture, water, water temperature,humidity, carbon monoxide, natural gas, propane gas, security alarms,intrusion alarms (e.g., open doors, broken windows, open windows, andthe like), other flammable gases, radon, poison gases, etc. Differentsensor units can be configured with different sensors or withcombinations of sensors. Thus, for example, in one installation thesensor units 102 and 104 could be configured with smoke and/ortemperature sensors while the sensor unit 103 could be configured with ahumidity sensor.

The discussion that follows generally refers to the sensor unit 102 asan example of a sensor unit, with the understanding that the descriptionof the sensor unit 102 can be applied to many sensor units. Similarly,the discussion generally refers to the repeater 110 by way of example,and not limitation. It will also be understood by one of ordinary skillin the art that repeaters are useful for extending the range of thesensor units 102-106 but are not required in all embodiments. Thus, forexample in one embodiment, one or more of the sensor units 102-106 cancommunicate directly with the base unit 112 without going through arepeater. It will also be understood by one of ordinary skill in the artthat FIG. 1 shows only five sensor units (102-106) and two repeaterunits (110-111) for purposes of illustration and not by way oflimitation. An installation in a large apartment building or complexwould typically involve many sensor units and repeater units. Moreover,one of ordinary skill in the art will recognize that one repeater unitcan service relatively many sensor units. In one embodiment, the sensorunit 102 can communicate directly with the base unit 112 without goingthrough a repeater 111.

When the sensor unit 102 detects an anomalous condition (e.g., smoke,fire, water, etc.) the sensor unit communicates with the appropriaterepeater unit 110 and provides data regarding the anomalous condition.The repeater unit 110 forwards the data to the base unit 112, and thebase unit 112 forwards the information to the computer 113. The computer113 evaluates the data and takes appropriate action. If the computer 113determines that the condition is an emergency (e.g., fire, smoke, largequantities of water), then the computer 113 contacts the appropriatepersonnel 120. If the computer 113 determines that the situationwarrants reporting, but is not an emergency, then the computer 113 logsthe data for later reporting. In this way, the sensor system 100 canmonitor the conditions in and around the building 101.

In one embodiment, the sensor unit 102 has an internal power source(e.g., battery, solar cell, fuel cell, etc.). In order to conservepower, the sensor unit 102 is normally placed in a low-power mode. Inone embodiment, using sensors that require relatively little power,while in the low power mode the sensor unit 102 takes regular sensorreadings and evaluates the readings to determine if an anomalouscondition exists. In one embodiment, using sensors that requirerelatively more power, while in the low power mode the sensor unit 102takes and evaluates sensor readings at periodic intervals. If ananomalous condition is detected, then the sensor unit 102 “wakes up” andbegins communicating with the base unit 112 through the repeater 110. Atprogrammed intervals, the sensor unit 102 also “wakes up” and sendsstatus information (e.g., power levels, self diagnostic information,etc.) to the base unit (or repeater) and then listens for commands for aperiod of time. In one embodiment, the sensor unit 102 also includes atamper detector. When tampering with the sensor unit 102 is detected,the sensor unit 102 reports such tampering to the base unit 112.

In one embodiment, the sensor unit 102 provides bi-directionalcommunication and is configured to receive data and/or instructions fromthe base unit 112. Thus, for example, the base unit 112 can instruct thesensor unit 102 to perform additional measurements, to go to a standbymode, to wake up, to report battery status, to change wake-up interval,to run self-diagnostics and report results, etc. In one embodiment, thesensor unit 102 reports its general health and status on a regular basis(e.g., results of self-diagnostics, battery health, etc.)

In one embodiment, the sensor unit 102 provides two wake-up modes, afirst wake-up mode for taking measurements (and reporting suchmeasurements if deemed necessary), and a second wake-up mode forlistening for commands from the central reporting station. The twowake-up modes, or combinations thereof, can occur at differentintervals.

In one embodiment, the sensor unit 102 uses spread-spectrum techniquesto communicate with the repeater unit 110. In one embodiment, the sensorunit 102 use frequency-hopping spread-spectrum. In one embodiment, thesensor unit 102 has an address or identification (ID) code thatdistinguishes the sensor unit 102 from the other sensor units. Thesensor unit 102 attaches its ID to outgoing communication packets sothat transmissions from the sensor unit 102 can be identified by therepeater 110. The repeater 110 attaches the ID of the sensor unit 102 todata and/or instructions that are transmitted to the sensor unit 102. Inone embodiment, the sensor unit 102 ignores data and/or instructionsthat are addressed to other sensor units.

In one embodiment, the sensor unit 102 includes a reset function. In oneembodiment, the reset function is activated by the reset switch 208. Inone embodiment, the reset function is active for a prescribed intervalof time. During the reset interval, the transceiver 203 is in areceiving mode and can receive the identification code from an externalprogrammer. In one embodiment, the external programmer wirelesslytransmits a desired identification code. In one embodiment, theidentification code is programmed by an external programmer that isconnected to the sensor unit 102 through an electrical connector. In oneembodiment, the electrical connection to the sensor unit 102 is providedby sending modulated control signals (power line carrier signals)through a connector used to connect the power source 206. In oneembodiment, the external programmer provides power and control signals.In one embodiment, the external programmer also programs the type ofsensor(s) installed in the sensor unit. In one embodiment, theidentification code includes an area code (e.g., apartment number, zonenumber, floor number, etc.) and a unit number (e.g., unit 1, 2, 3,etc.).

In one embodiment, the external programmer interfaces with thecontroller 202 by using an optional programming interface 210. In oneembodiment, the programming interface 210 includes a connector. In oneembodiment, the programming interface 210 includes an infraredinterface. In one embodiment, the programming interface 210 includes aninductive coupling coil. In one embodiment, the programming interface210 includes one or more capacitive coupling plates.

In one embodiment, the sensor communicates with the repeater on the 900MHz band. This band provides good transmission through walls and otherobstacles normally found in and around a building structure. In oneembodiment, the sensor communicates with the repeater on bands aboveand/or below the 900 MHz band. In one embodiment, the sensor, repeater,and/or base unit listen to a radio frequency channel before transmittingon that channel or before beginning transmission. If the channel is inuse, (e.g., by another device such as another repeater, a cordlesstelephone, etc.) then the sensor, repeater and/or base unit changes to adifferent channel. In one embodiment, the sensor, repeater and/or baseunit coordinate frequency hopping by listening to radio frequencychannels for interference and using an algorithm to select a nextchannel for transmission that avoids the interference. Thus, forexample, in one embodiment, if a sensor senses a dangerous condition andgoes into a continuous transmission mode, the sensor will test (e.g.,listen to) the channel before transmission to avoid channels that areblocked, in use, or jammed. In one embodiment, the sensor continues totransmit data until it receives an acknowledgement from the base unitthat the message has been received. In one embodiment, the sensortransmits data having a normal priority (e.g., status information) anddoes not look for an acknowledgement, and the sensor transmits datahaving elevated priority (e.g., excess smoke, temperature, etc.) untilan acknowledgement is received.

The repeater unit 110 is configured to relay communications trafficbetween the sensor 102 (and, similarly, the sensor units 103-104) andthe base unit 112. The repeater unit 110 typically operates in anenvironment with several other repeater units (such as the repeater unit111 in FIG. 1) and thus, the repeater unit 110 contains a database(e.g., a lookup table) of sensor unit IDs. In FIG. 1, the repeater 110has database entries for the Ids of the sensors 102-104, and thus, thesensor 110 will only communicate with sensor units 102-104. In oneembodiment, the repeater 110 has an internal power source (e.g.,battery, solar cell, fuel cell, etc.) and conserves power by maintainingan internal schedule of when the sensor units 102-104 are expected totransmit. In one embodiment, the repeater unit 110 goes to a low-powermode when none of its designated sensor units is scheduled to transmit.In one embodiment, the repeater 110 uses spread-spectrum techniques tocommunicate with the base unit 112 and with the sensor units 102-104. Inone embodiment, the repeater 110 uses frequency-hopping spread-spectrumto communicate with the base unit 112 and the sensor units 102-104. Inone embodiment, the repeater unit 110 has an address or identification(ID) code and the repeater unit 110 attaches its address to outgoingcommunication packets that originate in the repeater (that is, packetsthat are not being forwarded). In one embodiment, the repeater unit 110ignores data and/or instructions that are addressed to other repeaterunits or to sensor units not serviced by the repeater 110.

In one embodiment, the base unit 112 communicates with the sensor unit102 by transmitting a communication packet addressed to the sensor unit102. The repeaters 110 and 111 both receive the communication packetaddressed to the sensor unit 102. The repeater unit 111 ignores thecommunication packet addressed to the sensor unit 102. The repeater unit110 transmits the communication packet addressed to the sensor unit 102to the sensor unit 102. In one embodiment, the sensor unit 102, therepeater unit 110, and the base unit 112 communicate usingFrequency-Hopping Spread Spectrum (FHSS), also known as channel-hopping.

Frequency-hopping wireless systems offer the advantage of avoiding otherinterfering signals and avoiding collisions. Moreover, there areregulatory advantages given to systems that do not transmit continuouslyat one frequency. Channel-hopping transmitters change frequencies aftera period of continuous transmission, or when interference isencountered. These systems may have higher transmit power and relaxedlimitations on in-band spurs. FCC regulations limit transmission time onone channel to 400 milliseconds (averaged over 10-20 seconds dependingon channel bandwidth) before the transmitter must change frequency.There is a minimum frequency step when changing channels to resumetransmission. If there are 25 to 49 frequency channels, regulationsallow effective radiated power of 24 dBm, spurs must be −20 dBc, andharmonics must be −41.2 dBc. With 50 or more channels, regulations alloweffective radiated power to be up to 30 dBm.

In one embodiment, the sensor unit 102, the repeater unit 110, and thebase unit 112 communicate using FHSS wherein the frequency hopping ofthe sensor unit 102, the repeater unit 110, and the base unit 112 arenot synchronized such that at any given moment, the sensor unit 102 andthe repeater unit 110 are on different channels. In such a system, thebase unit 112 communicates with the sensor unit 102 using the hopfrequencies synchronized to the repeater unit 110 rather than the sensorunit 102. The repeater unit 110 then forwards the data to the sensorunit using hop frequencies synchronized to the sensor unit 102. Such asystem largely avoids collisions between the transmissions by the baseunit 112 and the repeater unit 110.

In one embodiment, the sensor units 102-106 all use FHSS and the sensorunits 102-106 are not synchronized. Thus, at any given moment, it isunlikely that any two or more of the sensor units 102-106 will transmiton the same frequency. In this manner, collisions are largely avoided.In one embodiment, collisions are not detected but are tolerated by thesystem 100. If a collision does occur, data lost due to the collision iseffectively re-transmitted the next time the sensor units transmitsensor data. When the sensor units 102-106 and repeater units 110-111operate in asynchronous mode, then a second collision is highly unlikelybecause the units causing the collisions have hopped to differentchannels. In one embodiment, the sensor units 102-106, repeater units110-111, and the base unit 112 use the same hop rate. In one embodiment,the sensor units 102-106, repeater units 110-111, and the base unit 112use the same pseudo-random algorithm to control channel hopping, butwith different starting seeds. In one embodiment, the starting seed forthe hop algorithm is calculated from the ID of the sensor units 102-106,repeater units 110-111, or the base unit 112.

In an alternative embodiment, the base unit communicates with the sensorunit 102 by sending a communication packet addressed to the repeaterunit 110, where the packet sent to the repeater unit 110 includes theaddress of the sensor unit 102. The repeater unit 102 extracts theaddress of the sensor unit 102 from the packet and creates and transmitsa packet addressed to the sensor unit 102.

In one embodiment, the repeater unit 110 is configured to providebi-directional communication between its sensors and the base unit 112.In one embodiment, the repeater 110 is configured to receiveinstructions from the base unit 110. Thus, for example, the base unit112 can instruct the repeater to: send commands to one or more sensors;go to standby mode; “wake up”; report battery status; change wake-upinterval; run self-diagnostics and report results; etc.

The base unit 112 is configured to receive measured sensor data from anumber of sensor units either directly, or through the repeaters110-111. The base unit 112 also sends commands to the repeater units110-111 and/or to the sensor units 102-106. In one embodiment, the baseunit 112 communicates with a diskless computer 113 that runs off of aCD-ROM. When the base unit 112 receives data from sensor units 102-106indicating that there may be an emergency condition (e.g., a fire orexcess smoke, temperature, water, etc.) the computer 113 will attempt tonotify the responsible party 120.

In one embodiment, the computer 113 maintains a database of the health,power status (e.g., battery charge), and current operating status of allof the sensor units 102-106 and the repeater units 110-111. In oneembodiment, the computer 113 automatically performs routine maintenanceby sending commands to each sensor unit 102-106 to run a self-diagnosticand report the results. The computer 113 collects and logs suchdiagnostic results. In one embodiment, the computer 113 sendsinstructions to each sensor units 102-106 telling the sensor how long towait between “wakeup” intervals. In one embodiment, the computer 113schedules different wakeup intervals to different sensor units 102-106based on the sensor unit's health, power status, location, etc. In oneembodiment, the computer 113 schedules different wakeup intervals todifferent sensor unit 102-106 based on the type of data and urgency ofthe data collected by the sensor unit (e.g., sensor units that havesmoke and/or temperature sensors produce data that should be checkedrelatively more often than sensor units that have humidity or moisturesensors). In one embodiment, the base unit sends instructions torepeaters to route sensor information around a failed repeater.

In one embodiment, the computer 113 produces a display that tellsmaintenance personnel which sensor units 102-106 need repair ormaintenance. In one embodiment, the computer 113 maintains a listshowing the status and/or location of each sensor according to the ID ofeach sensor.

In one embodiment, the sensor units 102-106 and/or the repeater units110-111 measure the signal strength of the wireless signals received(e.g., the sensor unit 102 measures the signal strength of the signalsreceived from the repeater unit 110, the repeater unit 110 measures thesignal strength received from the sensor unit 102 and/or the base unit112). The sensor units 102-106 and/or the repeater units 110-111 reportsuch signal strength measurement back to the computer 113. The computer113 evaluates the signal strength measurements to ascertain the healthand robustness of the sensor system 100. In one embodiment, the computer113 uses the signal strength information to re-route wirelesscommunications traffic in the sensor system 100. Thus, for example, ifthe repeater unit 110 goes offline or is having difficulty communicatingwith the sensor unit 102, the computer 113 can send instructions to therepeater unit 111 to add the ID of the sensor unit 102 to the databaseof the repeater unit 111 (and similarly, send instructions to therepeater unit 110 to remove the ID of the sensor unit 102), therebyrouting the traffic for the sensor unit 102 through the router unit 111instead of the router unit 110.

FIG. 2 is a block diagram of the sensor unit 102. In the sensor unit102, one or more sensors 201 and a transceiver 203 are provided to acontroller 202. The controller 202 typically provides power, data, andcontrol information to the sensor(s) 201 and the transceiver 203. Apower source 206 is provided to the controller 202. An optional tampersensor 205 is also provided to the controller 202. A reset device (e.g.,a switch) 208 is proved to the controller 202. In one embodiment, anoptional audio output device 209 is provided. In one embodiment, thesensor 201 is configured as a plug-in module that can be replacedrelatively easily.

In one embodiment, the transceiver 203 is based on a TRF 6901transceiver chip from Texas Instruments. Inc. In one embodiment, thecontroller 202 is a conventional programmable microcontroller. In oneembodiment, the controller 202 is based on a Field Programmable GateArray (FPGA), such as, for example, provided by Xilinx Corp. In oneembodiment, the sensor 201 includes an optoelectric smoke sensor with asmoke chamber. In one embodiment, the sensor 201 includes a thermistor.In one embodiment, the sensor 201 includes a humidity sensor. In oneembodiment, the sensor 201 includes a sensor, such as, for example, awater level sensor, a water temperature sensor, a carbon monoxidesensor, a moisture sensor, a water flow sensor, natural gas sensor,propane sensor, etc.

The controller 202 receives sensor data from the sensor(s) 201. Somesensors 201 produce digital data. However, for many types of sensors201, the sensor data is analog data. Analog sensor data is converted todigital format by the controller 202. In one embodiment, the controllerevaluates the data received from the sensor(s) 201 and determineswhether the data is to be transmitted to the base unit 112. The sensorunit 102 generally conserves power by not transmitting data that fallswithin a normal range. In one embodiment, the controller 202 evaluatesthe sensor data by comparing the data value to a threshold value (e.g.,a high threshold, a low threshold, or a high-low threshold). If the datais outside the threshold (e.g., above a high threshold, below a lowthreshold, outside an inner range threshold, or inside an outer rangethreshold), then the data is deemed to be anomalous and is transmittedto the base unit 112. In one embodiment, the data threshold isprogrammed into the controller 202. In one embodiment, the datathreshold is programmed by the base unit 112 by sending instructions tothe controller 202. In one embodiment, the controller 202 obtains sensordata and transmits the data when commanded by the computer 113.

In one embodiment, the tamper sensor 205 is configured as a switch thatdetects removal of or tampering with the sensor unit 102.

FIG. 3 is a block diagram of the repeater unit 110. In the repeater unit110, a first transceiver 302 and a second transceiver 304 are providedto a controller 303. The controller 303 typically provides power, data,and control information to the transceivers 302, 304. A power source 306is provided to the controller 303. An optional tamper sensor (not shown)is also provided to the controller 303.

When relaying sensor data to the base unit 112, the controller 303receives data from the first transceiver 302 and provides the data tothe second transceiver 304. When relaying instructions from the baseunit 112 to a sensor unit, the controller 303 receives data from thesecond transceiver 304 and provides the data to the first transceiver302. In one embodiment, the controller 303 conserves power bypowering-down the transceivers 302, 304 during periods when thecontroller 303 is not expecting data. The controller 303 also monitorsthe power source 306 and provides status information, such as, forexample, self-diagnostic information and/or information about the healthof the power source 306, to the base unit 112. In one embodiment, thecontroller 303 sends status information to the base unit 112 at regularintervals. In one embodiment, the controller 303 sends statusinformation to the base unit 112 when requested by the base unit 112. Inone embodiment, the controller 303 sends status information to the baseunit 112 when a fault condition (e.g., battery low) is detected.

In one embodiment, the controller 303 includes a table or list ofidentification codes for wireless sensor units 102. The repeater 110forwards packets received from, or sent to, sensor units 102 in thelist. In one embodiment, the repeater 110 receives entries for the listof sensor units from the computer 113. In one embodiment, the controller303 determines when a transmission is expected from the sensor units 102in the table of sensor units and places the repeater 110 (e.g., thetransceivers 302, 304) in a low-power mode when no transmissions areexpected from the transceivers on the list. In one embodiment, thecontroller 303 recalculates the times for low-power operation when acommand to change reporting interval is forwarded to one of the sensorunits 102 in the list (table) of sensor units or when a new sensor unitis added to the list (table) of sensor units.

FIG. 4 is a block diagram of the base unit 112. In the base unit 112, atransceiver 402 and a computer interface 404 are provided to acontroller 403. The controller 403 typically provides data and controlinformation to the transceivers 402 and to the interface. The interface404 is provided to a port on the monitoring computer 113. The interface404 can be a standard computer data interface, such as, for example,Ethernet, wireless Ethernet, firewire port, Universal Serial Bus (USB)port, bluetooth, etc.

FIG. 5 shows one embodiment of a communication packet 500 used by thesensor units, repeater units, and the base unit. The packet 500 includesa preamble portion 501, an address (or ID) portion 502, a data payloadportion 503, and an integrity portion 504. In one embodiment, theintegrity portion 504 includes a checksum. In one embodiment, the sensorunits 102-106, the repeater units 110-111, and the base unit 112communicate using packets such as the packet 500. In one embodiment, thepackets 500 are transmitted using FHSS.

In one embodiment, the data packets that travel between the sensor unit102, the repeater unit 111, and the base unit 112 are encrypted. In oneembodiment, the data packets that travel between the sensor unit 102,the repeater unit 111, and the base unit 112 are encrypted and anauthentication code is provided in the data packet so that the sensorunit 102, the repeater unit, and/or the base unit 112 can verify theauthenticity of the packet.

In one embodiment the address portion 502 includes a first code and asecond code. In one embodiment, the repeater 111 only examines the firstcode to determine if the packet should be forwarded. Thus, for example,the first code can be interpreted as a building (or building complex)code and the second code interpreted as a subcode (e.g., an apartmentcode, area code, etc.). A repeater that uses the first code forforwarding, thus, forwards packets having a specified first code (e.g.,corresponding to the repeater's building or building complex). Thus,alleviates the need to program a list of sensor units 102 into arepeater, since a group of sensors in a building will typically all havethe same first code but different second codes. A repeater soconfigured, only needs to know the first code to forward packets for anyrepeater in the building or building complex. This does, however, raisethe possibility that two repeaters in the same building could try toforward packets for the same sensor unit 102. In one embodiment, eachrepeater waits for a programmed delay period before forwarding a packet.Thus reducing the chance of packet collisions at the base unit (in thecase of sensor unit to base unit packets) and reducing the chance ofpacket collisions at the sensor unit (in the case of base unit to sensorunit packets). In one embodiment, a delay period is programmed into eachrepeater. In one embodiment, delay periods are pre-programmed onto therepeater units at the factory or during installation. In one embodiment,a delay period is programmed into each repeater by the base unit 112. Inone embodiment, a repeater randomly chooses a delay period. In oneembodiment, a repeater randomly chooses a delay period for eachforwarded packet. In one embodiment, the first code is at least 6digits. In one embodiment, the second code is at least 5 digits.

In one embodiment, the first code and the second code are programmedinto each sensor unit at the factory. In one embodiment, the first codeand the second code are programmed when the sensor unit is installed. Inone embodiment, the base unit 112 can re-program the first code and/orthe second code in a sensor unit.

In one embodiment, collisions are further avoided by configuring eachrepeater unit 111 to begin transmission on a different frequencychannel. Thus, if two repeaters attempt to begin transmission at thesame time, the repeaters will not interfere with each other because thetransmissions will begin on different channels (frequencies).

FIG. 6 is a flowchart showing one embodiment of the operation of thesensor unit 102 wherein relatively continuous monitoring is provided. InFIG. 6, a power up block 601 is followed by an initialization block 602.After initialization, the sensor unit 102 checks for a fault condition(e.g., activation of the tamper sensor, low battery, internal fault,etc.) in a block 603. A decision block 604 checks the fault status. If afault has occurred, then the process advances to a block 605 were thefault information is transmitted to the repeater 110 (after which, theprocess advances to a block 612); otherwise, the process advances to ablock 606. In the block 606, the sensor unit 102 takes a sensor readingfrom the sensor(s) 201. The sensor data is subsequently evaluated in ablock 607. If the sensor data is abnormal, then the process advances toa transmit block 609 where the sensor data is transmitted to therepeater 110 (after which, the process advances to a block 612);otherwise, the process advances to a timeout decision block 610. If thetimeout period has not elapsed, then the process returns to thefault-check block 603; otherwise, the process advances to a transmitstatus block 611 where normal status information is transmitted to therepeater 110. In one embodiment, the normal status informationtransmitted is analogous to a simple “ping” which indicates that thesensor unit 102 is functioning normally. After the block 611, theprocess proceeds to a block 612 where the sensor unit 102 momentarilylistens for instructions from the monitor computer 113. If aninstruction is received, then the sensor unit 102 performs theinstructions, otherwise, the process returns to the status check block603. In one embodiment, transceiver 203 is normally powered down. Thecontroller 202 powers up the transceiver 203 during execution of theblocks 605, 609, 611, and 612. The monitoring computer 113 can sendinstructions to the sensor unit 102 to change the parameters used toevaluate data used in block 607, the listen period used in block 612,etc.

Relatively continuous monitoring, such as shown in FIG. 6, isappropriate for sensor units that sense relatively high-priority data(e.g., smoke, fire, carbon monoxide, flammable gas, etc.). By contrast,periodic monitoring can be used for sensors that sense relatively lowerpriority data (e.g., humidity, moisture, water usage, etc.). FIG. 7 is aflowchart showing one embodiment of operation of the sensor unit 102wherein periodic monitoring is provided. In FIG. 7, a power up block 701is followed by an initialization block 702. After initialization, thesensor unit 102 enters a low-power sleep mode. If a fault occurs duringthe sleep mode (e.g., the tamper sensor is activated), then the processenters a wake-up block 704 followed by a transmit fault block 705. If nofault occurs during the sleep period, then when the specified sleepperiod has expired, the process enters a block 706 where the sensor unit102 takes a sensor reading from the sensor(s) 201. The sensor data issubsequently sent to the monitoring computer 113 in a report block 707.After reporting, the sensor unit 102 enters a listen block 708 where thesensor unit 102 listens for a relatively short period of time forinstructions from monitoring computer 708. If an instruction isreceived, then the sensor unit 102 performs the instructions, otherwise,the process returns to the sleep block 703. In one embodiment, thesensor 201 and transceiver 203 are normally powered down. The controller202 powers up the sensor 201 during execution of the block 706. Thecontroller 202 powers up the transceiver during execution of the blocks705, 707, and 708. The monitoring computer 113 can send instructions tothe sensor unit 102 to change the sleep period used in block 703, thelisten period used in block 708, etc.

In one embodiment, the sensor unit transmits sensor data until ahandshaking-type acknowledgement is received. Thus, rather than sleep ofno instructions or acknowledgements are received after transmission(e.g., after the decision block 613 or 709) the sensor unit 102retransmits its data and waits for an acknowledgement. The sensor unit102 continues to transmit data and wait for an acknowledgement until anacknowledgement is received. In one embodiment, the sensor unit acceptsan acknowledgement from a repeater unit 111 and it then becomes theresponsibility of the repeater unit 111 to make sure that the data isforwarded to the base unit 112. In one embodiment, the repeater unit 111does not generate the acknowledgement, but rather forwards anacknowledgement from the base unit 112 to the sensor unit 102. Thetwo-way communication ability of the sensor unit 102 provides thecapability for the base unit 112 to control the operation of the sensorunit 102 and also provides the capability for robust handshaking-typecommunication between the sensor unit 102 and the base unit 112.

Regardless of the normal operating mode of the sensor unit 102 (e.g.,using the Flowcharts of FIGS. 6, 7, or other modes) in one embodiment,the monitoring computer 113 can instruct the sensor unit 102 to operatein a relatively continuous mode where the sensor repeatedly takes sensorreadings and transmits the readings to the monitoring computer 113. Sucha mode would can be used, for example, when the sensor unit 102 (or anearby sensor unit) has detected a potentially dangerous condition(e.g., smoke, rapid temperature rise, etc.)

FIG. 8 shows a sensor system 800 wherein one or more relatively low-costsensor units 802-804 provides sensor readings and/or status informationto an area monitor unit 810 that communicates with the base unit 112 orwith a repeater unit 110. The sensor units 802-804 can be configured asembodiments of the sensor unit 102 and/or as embodiments of the moisturesensor unit 1010. In one embodiment, the sensor units 802 and 804 areconfigured for one-way communication to transmit information to the areamonitor 810. The moisture sensor unit 1010 can be configured as oneembodiment of the sensor unit 102. The moisture sensor unit 1010 can beconfigured as shown in FIG. 2 with a transceiver 203 that can bothtransmit and receive, or the transceiver 203 can be configured fortransmit-only operation. In one embodiment, the area monitor 810 isconfigured in a manner similar to the repeater unit 110.

In one embodiment, the area monitor 810 is configured to providebi-directional communication with one or more sensor units 102. In oneembodiment, the area monitor 810 is configured to receive one-waycommunication from one or more sensor units 802-804.

In one embodiment, the sensor unit 802 sends a message to the areamonitor 810 whenever an anomalous sensor reading is detected (e.g.,water is detected, smoke is detected, etc.). In one embodiment, thesensor unit 802 sends a stream of messages spaced at desired intervals(e.g., every few seconds) to the area monitor 810 whenever an anomaloussensor reading is detected. In one embodiment, the sensor unit 802 sendsa status report (e.g., system health, battery power status, etc.) to thearea monitor 810 at a desired regular interval (e.g., every hour, everyday, every few hours, etc.). The area monitor forwards messages from thesensor system 800 to the monitoring system 113. In one embodiment, themonitoring system 113 and/or area monitor 810 can determine that thesensor unit 802 has failed based on status information received from thesensor unit 802 and/or based on a lack of status information from thesensor unit 802. The area monitor 810 expects to receive periodic statusupdates from the sensor 802, thus, the area monitor (and the centralmonitor 113) can assume that the sensor unit 802 has failed or beenremoved if such regular status updates are not received.

In one embodiment, the sensor unit 802 send actual sensor data to thearea monitor 810 and the area monitor forwards such data to the centralmonitoring system 113 for analysis. Thus, unlike simple alarm systemsthat simply provide on/off-type sensors, the sensor units 802-804 and102-106 provide actual sensor readings that can be analyzed by themonitoring system to determine or estimate the severity of a problem(e.g., the amount of smoke, the amount of water, the rate of increase insmoke, water, temperature, etc.).

In one embodiment, the monitoring system 113 maintains data receivedfrom the sensor units 802-804 and 102-106 to help in maintenance of thesensor system. In one embodiment, maintenance personnel are expected totest each sensor unit on a regular basis (e.g., semi-annually, annually,bi-annually, monthly, etc.) to make sure the sensor is working. Thus,for example, in one embodiment, the maintenance personnel are expectedto expose each moisture sensor 1010 to water to test the operation ofthe sensor and to make sure that a “water-sensed” message is transmittedto the monitoring system 113. Similarly, the maintenance personnel canbe tasked with exposing each smoke sensor to smoke. Thus, if themonitoring system database shows that a particular sensor unit has notreported a sensor event (e.g., water detected, smoke detected, etc.) ina period corresponding to the maintenance interval, the monitoringsystem 113 can report that the sensor unit has failed or that the sensorunit has not been tested according to the testing schedule. In thismanner, supervisory personnel can monitor the actions of maintenancepersonnel by examining the database maintained by the system 113 to makesure that each sensor has been activated and tested according thedesired maintenance schedule.

The database maintained by the monitoring system 113 can also be used toprovide plots of sensor activations and to indicate possible troubleareas in a building or structure. Thus, for example, if a particularwater sensor has been activated on a regular basis, the monitoringsystem 113 can indicate that a potential problem exists in the areamonitored by that sensor and thus, alert the maintenance or supervisorypersonnel.

Excess moisture in a structure can cause severe problems such asrotting, growth of molds, mildew, and fungus, etc. (hereinafter referredto generically as fungus). In one embodiment, the sensor 201 includes amoisture sensor. In one embodiment, the monitoring system 100 detectsconditions favorable for fungus (e.g., mold, mildew, fungus, etc.)growth by measuring moisture content of the building material at one ormore locations of a building. In one embodiment, sensor system is usedto detect moisture in building materials, such as, for example, drywall,wood, concrete, plaster, stucco, etc. In one embodiment, the sensor unit102 includes a moisture sensor and one or more moisture probes coupledto the building material. The moisture probes are provided to thebuilding material to allow the sensor unit 102 to detect and/or measurethe presence of moisture in the material. Moisture in the buildingmaterial is generally the result of a leak (e.g., plumbing leak, roofleak, stucco leak, etc.), invasion of ground water, trapped humidity, orcondensation. In one embodiment, the severity of a moisture problem isascertained by the sensor unit 102 (or the monitoring computer 113) bymeasuring (or estimating) the rate of rise in the moisture level and/orby measuring (or estimating) the size of a moist area, and/or bymeasuring (or estimating) the amount of moisture in the buildingmaterial.

In one embodiment, the monitoring computer 113 compares moisturemeasurements taken from different sensor units in order to detect areasthat have excess moisture. Thus, for example, the monitoring computer113 can compare the moisture readings from a first sensor unit 102 in afirst attic area, to a moisture reading from a second sensor unit 102 ina second area. For example, the monitoring computer can take moisturereadings from a number of attic areas to establish a baseline moisturereading and then compare the specific moisture readings from varioussensor units to determine if one or more of the units are measuringexcess moisture. The monitoring computer 113 would flag areas of excessmoisture for further investigation by maintenance personnel. In oneembodiment, the monitoring computer 113 maintains a history of moisturereadings for various sensor units and flags areas that show anunexpected increase in moisture for investigation by maintenancepersonnel.

The monitoring station 113 collects moisture readings from the firstmoisture sensor and the second moisture sensor and indicates conditionsfavorable for fungus growth by comparing the first moisture data and thesecond moisture data. In one embodiment, the monitoring station 113establishes a baseline moisture by comparing moisture readings from aplurality of moisture sensors and indicates possible fungus growthconditions in the first building area when at least a portion of thefirst moisture data exceeds the baseline moisture by a specified amount.In one embodiment, the monitoring station 113 establishes a baselinemoisture by comparing moisture readings from a plurality of moisturesensors and indicates possible fungus growth conditions in the firstbuilding area when at least a portion of the first moisture data exceedsthe baseline moisture by a specified percentage.

In one embodiment, the monitoring station 113 establishes a baselinemoisture history by comparing moisture readings from a plurality ofmoisture sensors and indicates possible fungus growth conditions in thefirst building area when at least a portion of the first moisture dataexceeds the baseline moisture history by a specified amount over aspecified period of time. In one embodiment, the monitoring station 113establishes a baseline moisture history by comparing moisture readingsfrom a plurality of moisture sensors over a period of time and indicatespossible fungus growth conditions in the first building area when atleast a portion of the first moisture data exceeds the baseline moistureby a specified percentage of a specified period of time.

In one embodiment, the sensor unit 102 transmits moisture data when itdetermines that the moisture data fails a threshold test. In oneembodiment, the moisture threshold for the threshold test is provided tothe sensor unit 102 by the monitoring station 113. In one embodiment,the moisture threshold for the threshold test is computed by themonitoring station from a baseline moisture established in themonitoring station. In one embodiment, the baseline moisture is computedat least in part as an average of moisture readings from a number ofmoisture sensors. In one embodiment, the baseline moisture is computedat least in part as a time average of moisture readings from a number ofmoisture sensors. In one embodiment, the baseline moisture is computedat least in part as a time average of moisture readings from a moisturesensor. In one embodiment, the baseline moisture is computed at least inpart as the lesser of a maximum moisture reading an average of a numberof moisture readings.

In one embodiment, the sensor unit 102 reports moisture readings inresponse to a query by the monitoring station 113. In one embodiment,the sensor unit 102 reports moisture readings at regular intervals. Inone embodiment, a moisture interval is provided to the sensor unit 102by the monitoring station 113.

In one embodiment, the calculation of conditions for fungus growth iscomparing moisture readings from one or more moisture sensors to thebaseline (or reference) moisture. In one embodiment, the comparison isbased on comparing the moisture readings to a percentage (e.g.,typically a percentage greater than 100%) of the baseline value. In oneembodiment, the comparison is based on comparing the moisture readingsto a specified delta value above the reference moisture. In oneembodiment, the calculation of likelihood of conditions for fungusgrowth is based on a time history of moisture readings, such that thelonger the favorable conditions exist, the greater the likelihood offungus growth. In one embodiment, relatively high moisture readings overa period of time indicate a higher likelihood of fungus growth thanrelatively high moisture readings for short periods of time. In oneembodiment, a relatively sudden increase in moisture as compared to abaseline or reference moisture is reported by the monitoring station 113as a possibility of a water leak. If the relatively high moisturereading continues over time then the relatively high moisture isreported by the monitoring station 113 as possibly being a water leakand/or an area likely to have fungus growth or water damage.

Temperatures relatively more favorable to fungus growth increase thelikelihood of fungus growth. In one embodiment, temperature measurementsfrom the building areas are also used in the fungus grown-likelihoodcalculations. In one embodiment, a threshold value for likelihood offungus growth is computed at least in part as a function of temperature,such that temperatures relatively more favorable to fungus growth resultin a relatively lower threshold than temperatures relatively lessfavorable for fungus growth. In one embodiment, the calculation of alikelihood of fungus growth depends at least in part on temperature suchthat temperatures relatively more favorable to fungus growth indicate arelatively higher likelihood of fungus growth than temperaturesrelatively less favorable for fungus growth. Thus, in one embodiment, amaximum moisture and/or minimum threshold above a reference moisture isrelatively lower for temperature more favorable to fungus growth thanthe maximum moisture and/or minimum threshold above a reference moisturefor temperatures relatively less favorable to fungus growth.

In one embodiment, a water flow sensor is provided to the sensor unit102. The sensor unit 102 obtains water flow data from the water flowsensor and provides the water flow data to the monitoring computer 113.The monitoring computer 113 can then calculate water usage.Additionally, the monitoring computer can watch for moisture, by, forexample, looking for water flow when there should be little or no flow.Thus, for example, if the monitoring computer detects water usagethroughout the night, the monitoring computer can raise an alertindicating that a possible water leak has occurred.

In one embodiment, a rain sensor is provided to the monitoring computer113 and one or more water shutoff valves are provided to the monitoringcomputer 113 to allow the monitoring computer 113 to shut off the watersupply to one or more areas of a building. If one or more moisturesensors report a relatively rapid rise in moisture levels when it is notraining, then the monitoring computer can shut off the water supply tothe affected area of the buildings (on the assumption that the moistureis coming from a plumbing leak).

FIG. 9 shows a moisture sensor unit 902 that includes an impedancesensor 901 provided to an impedance probe 903. The sensor unit 902 isone embodiment of the sensor units 102 or 802 wherein the sensor 201 isconfigured as an impedance sensor 901. The impedance sensor 901 measuresthe impedance of the probe 903. In one embodiment, the impedance sensor901 measures a resistance of the probe 903. In one embodiment, theimpedance sensor 901 measures an AC resistance of the probe 903. In oneembodiment, the impedance sensor 901 measures an AC reactance of theprobe 903. The impedance sensor 901 receives a control input from thecontroller 202 and provides output data to the controller 202.

The impedance of most building materials varies as the moisture contentof the building material changes. Typically, most building materials(e.g., concrete, drywall, plaster, wood, etc.) have a relatively highimpedance when dry, and the impedance goes down as the moisture levelincreases. Thus, one convenient way to measure the moisture content ofmany building materials is to measure the impedance of a probe providedto the building material.

If only the DC resistance is desired, then the probe is provided indirect electrical contact with the building material. If the ACimpedance is desired, then the probe can be provided in directelectrical contact with the building material or the probe can becapacitively coupled to the building material through a dielectric.

The probe is typically provided to the building material when thematerial is dry. The impedance sensor measures the impedance of theprobe at specified intervals. In one embodiment, a change in theimpedance is reported by the sensor unit 902 to the monitoring system113 as a possible increase in moisture content.

In one embodiment, the measured impedance data, the electricalcharacteristics of the probe, and the type of building material to whichthe probe is attached are provided to the monitoring system 113 to allowthe monitoring system 113 to compute a moisture content value from theimpedance data.

In one embodiment, a threshold value (as described above) is provided tothe sensor unit 902 and the sensor unit reports impedance data when themeasured impedance values cross the threshold. In one embodiment, thethreshold is an upper threshold, and the impedance data is reported whenthe measured impedance values exceed the threshold. In one embodiment,the threshold is a lower threshold, and the impedance data is reportedwhen the measured impedance values fall below the threshold. In oneembodiment, the threshold is configured as an inner range. In oneembodiment, the threshold is configured as an outer range. In oneembodiment, a threshold is provided for the magnitude of the impedance.In one embodiment, a threshold is provided for the real part of theimpedance (e.g., the resistance). In one embodiment, a threshold isprovided for the imaginary part of the impedance (e.g., the reactance).

For example, drywall (gypsum) and/or plaster have a relatively highimpedance with dry and the impedance drops as the moisture contentincreases. In one embodiment, the sensor unit 902 reports impedance datato the monitoring system 113 whenever the impedance measured by theimpedance sensor 1002 drops by a specified amount. In one embodiment,the sensor unit 902 reports impedance data to the monitoring system 113whenever the impedance measured by the impedance sensor 1002 drops by aspecified amount, where the specified amount is specified according tothe type of material the probe 1001 is attached to.

In one embodiment, the sensor unit 902 reports impedance data to themonitoring system 113 at specified intervals and whenever the impedancemeasured by the impedance sensor 1002 drops by a specified amount. Themonitoring system 113 establishes a “dry” impedance value by recordingthe highest impedance reported by the sensor unit 902.

FIG. 10 shows an impedance sensor 1002 (corresponding to the impedancesensor 902 from FIG. 9) provided to an impedance probe 1001 configuredas a pair of conductive strips 1008, 1009. Optionally, in oneembodiment, two or more pins 1010, 1011 are provided to the conductivestrips 1008, 1009. In one embodiment, when the probe 1001 is installed,the pins 1010, 1011 are inserted into the building material in order toprovide better electrical contact with the building material. The pins1010, 1011 can be configured as sharp pins attached to the strips 1008,1009, nails and/or staples driven through the strips 1008, 1009, etc.

In response to the control input from the controller 202, the impedancesensor measures the impedance of the probe 1001. In one embodiment, theexpected impedance values for wet and moist conditions are determinedfrom the type of building material and the characteristics of the probe1001 (e.g., length, number of pins, etc.).

FIG. 11 is a schematic of an impedance sensor 1002 configured to measureimpedance by using a voltage source 1904 and a current sensor 1105. Thevoltage source provides a voltage between the conductors 1008, 1009, andthe current sensor 1105 then measures the current through the probe. Theimpedance is then calculated by using Ohm's law. In one embodiment, thecontroller 202 controls the voltage produced by the voltage source 1104.In one embodiment, the voltage source 1104 is a DC source. In oneembodiment, the voltage source 1104 is an AC source. In one embodiment,the controller 202 controls the frequency and/or phase of the voltagesource 1104. In one embodiment, the current sensor 1105 measuresmagnitude of the current through the current through the probe 1001. Inone embodiment, the current sensor 1105 measures magnitude and phase ofthe current through the current through the probe 1001.

FIG. 12 is a schematic of an impedance sensor 1002 configured to measureimpedance by using a current source 1204 and a voltage sensor 1205. Thecurrent source 1204 provides a current through the conductors 1008,1009, and the voltage sensor 1205 then measures the voltage across theprobe 1001. The impedance is then calculated by using Ohm's law. In oneembodiment, the controller 202 controls the current produced by thecurrent source 1204. In one embodiment, the current source 1204 is a DCsource. In one embodiment, the current source 1204 is an AC source. Inone embodiment, the controller 202 controls the frequency and/or phaseof the current source 1204. In one embodiment, the voltage sensor 1205measures magnitude of the current through the voltage across the probe1001. In one embodiment, the current sensor 1205 measures magnitude andphase of the voltage across the current through the probe 1001.

FIG. 13 is a schematic of an impedance sensor 1002 configured to measureimpedance using an impedance bridge that includes impedances 1301-1303in three legs of the bridge, and the probe is provided to the fourth legof the bridge. The control input is provided to a voltage source thatdrives the bridge and to a module 1310 that measures the impedanceacross the bridge. In one embodiment, the impedance 1303 is fixed. Inone embodiment, the impedance 1303 is varied by the control module 1310.In one embodiment, the impedance 1303 is fixed. In one embodiment, theimpedance 1303 is varied by the control module 1310 in response to thecontrol input. The impedance of across the probe 1001 is then calculatedas known in the art by using the known impedances 1301-1303 and thevoltage across the bridge.

FIG. 14 shows a moisture sensor that includes a time/frequency domainimpedance sensor 1402 provided to the impedance probe 1001. In oneembodiment, the time-frequency domain impedance sensor 1402 usestime-domain and/or frequency domain measurement techniques to measurethe impedance properties along the impedance probe 1001. In oneembodiment, the time-frequency domain impedance sensor 1402 usestime-domain measurement techniques to measure the impedance propertiesalong the impedance probe 1001 by sending a relatively short pulse ofenergy along the impedance probe 1001 and measuring the reflections ofthe energy pulse. In one embodiment, the time-frequency domain impedancesensor 1402 is configured as a time-domain reflectometer. In oneembodiment, the time-frequency domain impedance sensor 1402 measures theimpedance of the impedance probe 1001 at various frequencies, and thenuses Fourier transform techniques to transform the measurements from thefrequency domain into the time domain. In one embodiment, thetime-domain data are used to identify regions along the impedance probe1001 that are relatively more moist.

FIG. 15 is a plot showing an example output of the time-frequency domainimpedance sensor 1402 when a relatively small damp area 1502 isdetected. When the impedance probe 1001 is provided to a buildingmaterial that has a smaller impedance when moist, the impedance of theimpedance probe 1001 is smaller in the region 1502 and thus theimpedance probe 1001 produces a reflection corresponding to the region1502. By way of example, FIG. 15 includes a graph 1530 showing thereduced resistance corresponding to the region 1502.

FIG. 16 is a plot showing an example output of the time-frequency domainimpedance sensor 1402 when a relatively larger damp area 1602 isdetected. When the impedance probe 1001 is provided to a buildingmaterial that has a smaller impedance when moist, the impedance of theimpedance probe 1001 is smaller in the region 1502 and thus, theimpedance probe 1001 produces a reflection corresponding to the region1001. By way of example, FIG. 16 includes a graph 1630 showing thereduced resistance corresponding to the region 1502. Comparison of thegraphs 1530 and 1630 shows that the time/frequency domain impedancesensor 1402 can be used to provide an indication of the location, size,and severity of the moist area. The location of the moist area isindicated by the location of the moist area along the impedance probe1001 (where time can be converted into a distance along the probeaccording to the speed of propagation of an electrical signal along theprobe). The size of the moist area is indicated by the size of theregion of lower impedance along the impedance probe 1001. The amount ofmoisture in the building material at different points along theimpedance probe 1001 is computed from the measured impedance at variouspoints along the impedance probe 1001 and knowledge of the properties ofthe building material provided to the impedance probe.

In one embodiment, the time/frequency impedance sensor 1402 isconfigured according to the schematics shown in FIGS. 11-13 where therespective sources (voltage and/or current sources) are configured as AC(Alternating Current) sources or sources that produce a time-domainand/or frequency-domain waveform.

FIG. 17 is a schematic of one embodiment of the time/frequency domainimpedance sensor 1402 configured as a pulse reflectometer having a pulsegenerator 1705, a diplexer switch 1703, and a sampler 1704. A timinggenerator 1701 is controlled by the control input and provides controloutputs to the pulse generator 1705, the diplexer switch 1703, and thesampler 1704. The diplexer switch 1703 is typically an electronic switchconfigured using solid-state electronic elements to provide high speedand high reliability.

In a transmit mode, the timing generator places the diplexer switch 1703in a “transmit position” (as shown), and instructs the pulse generator1705 to provide a pulse of relatively-short time duration (e.g.,implses, chirps, frequency pulses, etc) to the diplexer switch 1703. Thediplexer switch 1703 provides the pulse to the impedance probe 1001. Thetiming generator then switches the diplexer switch 1703 to a “receiveposition” wherein when return pulse (or pulses) from the impedance probe1001 are provided to the sampler 1704. The sampler 1704. The samplerprovides sampled data from the impedance probe 1001 to the controller202.

In one embodiment, the moisture sensor unit 902 is configured as anadjustable-threshold moisture sensor that computes a threshold level. Inone embodiment, the threshold is computed as an average of a number ofsensor measurements. In one embodiment, the average value is arelatively long-term average. In one embodiment, the average is atime-weighted average wherein recent sensor readings used in theaveraging process are weighted differently than less recent sensorreadings. In one embodiment, more recent sensor readings are weightedrelatively more heavily than less recent sensor readings. In oneembodiment, more recent sensor readings are weighted relatively lessheavily than less recent sensor readings. The average is used to set thethreshold level. When the moisture sensor readings rise above thethreshold level, the moisture sensor indicates a notice condition. Inone embodiment, the moisture sensor indicates a notice condition whenthe moisture sensor reading rises above the threshold value for aspecified period of time. In one embodiment, the moisture sensorindicates a notice condition when a statistical number of sensorreadings (e.g., 3 of 2, 5 of 3, 10 of 7, etc.) are above the thresholdlevel. In one embodiment, the moisture sensor unit 902 indicates variouslevels of alarm (e.g., warning, alert, alarm) based on how far above thethreshold the moisture sensor reading has risen.

In one embodiment, the moisture sensor unit 902 computes the noticelevel according to how far the moisture sensor readings have risen abovethe threshold and how rapidly the moisture sensor readings have risen orhow long the moisture reading have been elevated. A relatively fast rateof rise may be indicative of a relatively serious leak and/or arelatively large volume of water that could lead to water damage. Anarea that has been moist (even slightly moist) for a period of time maybe indicative of long-term damage due to molds, fungus, rotting, etc.For example, for purposes of explanation, the level of readings and therate of rise can be quantified as low, medium, and high. The combinationof sensor reading level and rate of rise then can be show as a table, asshow in Table 1. Tables 1 and 2 provide examples and is provided by wayof explanation, not limitation.

TABLE 1 Sensor Reading Level (as compared to the threshold) Rate of RiseHigh Warning Alarm Alarm Medium Notice Warning Alarm Low Notice WarningAlarm Low Medium High

TABLE 2 Sensor Reading Level (as compared to the threshold) Length ofTime Long Alarm Alarm Alarm Medium Warning Warning Alarm Short NoticeWarning Alarm Low Medium High

One of ordinary skill in the art will recognize that the notice level Ncan be expressed as an equation N=f(l, v, r, t), where l is thethreshold level, v is the moisture sensor reading, r is the rate ofrise, and t is the length of time of the moisture sensor reading. Inembodiments where the size of the moist area can be measured (asdescribed, for example, in connection with FIGS. 13-17), then the sizeof the moist area can also be included in the above equation and/or inthe above tables. In one embodiment, the moisture sensor reading vand/or the rate of rise r are lowpass filtered in order to reduce theeffects of noise in the moisture sensor readings. In one embodiment, thethreshold is computed by lowpass filtering the moisture sensor readingsv using a filter with a relatively low cutoff frequency. A filter with arelatively low cutoff frequency produces a relatively long-termaveraging effect. In one embodiment, separate thresholds are computedfor the moisture sensor reading and for the rate of rise.

In one embodiment, a calibration procedure period is provided when themoisture sensor unit 902 is powered up. During the calibration period,the moisture sensor data values from the moisture sensor 201 are used tocompute the threshold value, but the moisture sensor does not computenotices, warnings, alarms, etc., until the calibration period iscomplete. In one embodiment, the moisture sensor unit 902 uses a fixed(e.g., pre-programmed) threshold value to compute notices, warnings, andalarms during the calibration period and then uses the adjustablethreshold value once the calibration period has ended.

In one embodiment, the moisture sensor unit 902 determines that afailure of the moisture sensor 201 has occurred when the adjustablethreshold value exceeds a maximum adjustable threshold value. In oneembodiment, the moisture sensor unit 902 determines that a failure ofthe moisture sensor 201 has occurred when the adjustable threshold valuefalls below a minimum adjustable threshold value. The moisture sensorunit 902 can report such failure of the moisture sensor 201 to the baseunit 112.

In one embodiment, the moisture sensor unit 902 obtains a number ofsensor data readings from the moisture sensor 201 and computes thethreshold value as a weighted average using a weight vector. The weightvector weights some sensor data readings relatively more than othersensor data readings.

In one embodiment, the moisture sensor unit 902 obtains a number ofsensor data readings from the moisture sensor unit 201 and filters themoisture sensor data readings and calculates the threshold value fromthe filtered sensor data readings. In one embodiment, the moisturesensor unit applies a lowpass filter. In one embodiment, the moisturesensor unit 201 uses a Kalman filter to remove unwanted components fromthe moisture sensor data readings. In one embodiment, the moisturesensor unit 201 discards sensor data readings that are “outliers” (e.g.,too far above or too far below a normative value). In this manner, themoisture sensor unit 902 can compute the threshold value even in thepresence of noisy sensor data.

In one embodiment, the moisture sensor unit 902 indicates a noticecondition (e.g., alert, warning, alarm) when the threshold value changestoo rapidly. In one embodiment, the moisture sensor unit 902 indicates anotice condition (e.g., alert, warning, alarm) when the threshold valueexceeds a specified maximum value. In one embodiment, the moisturesensor unit 902 indicates a notice condition (e.g., alert, warning,alarm) when the threshold value falls below a specified minimum value.

In one embodiment, the moisture sensor unit 902 adjusts one or moreoperating parameters of the moisture sensor 201 according the thresholdvalue. Thus, for example, in the example of a moisture sensor, themoisture sensor unit 201 can adjust the voltage (or current) provided tothe moisture probe.

FIG. 18 is a rear view showing one embodiment of the impedance probe1001 configured as a molding system 1800. The molding system 1800includes linear conductors 1801 and 1802 provided substantially alongthe length of a molding 1805. The molding 1805 can be configured as atypical decorative molding, such as, for example, a baseboard molding,door-jamb molding, crown molding, wainscot molding, etc. In oneembodiment, the conductors 1801, 1802 are relatively smooth andconfigured to be capacitively coupled to a building material. In onecapacitive coupling embodiment, the conductors are covered by arelatively thin layer of dielectric. In one embodiment, a plurality ofsharp pins (e.g., pins 1803, 1804) are provide to electrically connectthe conductors 1801, 1802 pierce into a wall or other building structurewhen the molding 1805 is attached to the wall (or structure). In oneembodiment, the conductors 1801, 1802 and the optional pins (e.g., thepins 1803, 1804) are provided to the molding 1805 during manufacture. Aswith conventional molding, moldings according to the molding system 1800are purchased, cut to length, and attached to a building by nails, glue,staples, screws, etc.

In one embodiment, connector pins 1808 and 1809 are provided to theconductors 1801 and 1802 respectively. The optional connector pins 1808,1809 extend through to the front of the molding 1805 to provideelectrical connection to sensor unit 802 provided to the front of themolding 1805, as shown in FIG. 19.

FIG. 20 shows the impedance probe 1001 configured as a relativelyflexible tape 2000. In the tape 2000, the linear conductors 1801 and1802 are provided to a dielectric substrate 2001 (e.g., plastic, mylar,nylon, etc.). In one embodiment, the conductors 1801, 1802 arerelatively smooth and configured to be capacitively coupled to abuilding material. In one capacitive coupling embodiment, the conductorsare covered by a relatively thin layer of dielectric. In one embodiment,the tape 2000 is attached to the desired building material by anadhesive. In one embodiment, the tape 2000 is attached to the desiredbuilding material by a plurality of staples (or nails) driven throughthe conductors 1801 and 1802 so as to provide electrical connectionbetween the conductors and the building material.

In one embodiment, a plurality of sharp pins (e.g., pins 1803, 1804) areprovide to electrically connect the conductors 1801, 1802 pierce into awall or other building structure when the molding 1805 is attached tothe wall (or structure). In one embodiment, an adhesive layer with apeel-off protective cover 2002 is provide to the back of the substrate.The adhesive can be used to attach the tape 2002 to a molding (or otherbuilding material) before the molding is installed.

As shown in FIG. 21, an adhesive and a peel-off layer 2101 can also(either along with the adhesive and peel-off 2002 or in the alternative)be installed on the front of the tape 2000 to allow the tape 2000 to beinstalled before any covering of molding. Thus, the tape 2000 can alsobe installed to studs before drywall is installed, installed betweenstuds, installed to flooring, attached to the inner surfaces of outerwalls, etc.

FIG. 22 shows one installation of the moisture sensor unit 902 to theimpedance probe tape 2000 provided between a wall 2201 and a molding2209. The sensor unit 902 is mounted to the wall and the tape 2000 isconfigured to extend past the end of the molding 2209 and under thesensor unit 902 (between the wall and the sensor unit 902). In oneembodiment, a plurality of spikes or pins 2210 are provided to thesensor unit 902 to allow the sensor unit to make electrical contact withthe conductors 1801, 1802 in the tape 2000.

FIG. 23 shows an alternative installation of the moisture sensor unit902 to the impedance probe tape 2000 provided between the wall 2201 andthe molding 2209. In FIG. 23, the tape 2000 is configured to extend pastthe end of the molding 2209 and is wrapped around the end of the molding2209 and onto the face of the molding 2209. The sensor unit 902 ismounted to the face of the molding with a portion of the tape 2000between the sensor unit and the face of the molding. In one embodiment,one or more conductive pads 2310 are provided on the back of the sensorunit 902 to allow the sensor unit to make electrical contact with theconductors 1801, 1802 in the tape 2000 (and/or with the pins 1803,1804).

FIG. 24 shows one example of an installation of the impedance probe tape2000 wrapped around a corner. In FIG. 24 a first piece 2402 of impedanceprobe tape 2000 is mounted between a first section of wall 2401 and afirst molding 2409. A second piece 2403 of impedance probe tape 2000 ismounted between a second section of wall 2411 and a second molding 2410.A portion of the first piece 2402 extends past the end of the molding2409, wraps around the corner between the walls 2401 and 2411, andextends between the molding 2410 and the wall 2411. The piece 2402overlaps the piece 2403 in a region 2404. Pins 1803, 1804 on the piece2402 make electrical contact with the conductors 1801, 1802 on the piece2403.

FIG. 25 shows one example of an installation of two shorter pieces ofthe impedance probe tape 2000 installed under a relatively long molding.In FIG. 25 a first piece 2503 of impedance probe tape 2000 is mountedbetween a wall 2501 and a molding 2509. A second piece 2502 of impedanceprobe tape 2000 is mounted between the wall 2501 and the molding 2509such that a portion of the first piece 2503 overlaps a second piece 2502in an overlap region. Pins 1803, 1804 on the piece 2502 make electricalcontact with the conductors 1801, 1802 on the piece 2501.

FIG. 26 shows a self-test unit 2602 for use in connection with themoisture sensor unit 902. The self-test unit 2602 is similar to themoisture sensor unit 902 and includes the antenna 204, the transceiver203, the controller 202, and the power source 206. A control input fromthe controller 202 is provided to a testing module 2610. The testingmodule 2610 includes a test impedance 2611 and anelectronically-controlled switch 2612. The switch 2612 is configured toprovide the test impedance 2611 to the impedance probe 903 when theswitch 2612 is activated by the control input. In one embodiment, thecontrol input can also be used to vary the impedance Z of the testimpedance 2611. In one embodiment, the monitoring system 113 sendsinstructions to the self-test unit 2602 to control the impedance Z ofthe test impedance 2611.

When instructed, the self-test unit 2602 connects the test impedance2611 to the impedance probe 903. The moisture sensor 902, also providedto the impedance probe 903, can then be used to measure the impedance ofthe impedance probe. The moisture sensor 902 can expect to measure thean impedance corresponding to the combination of the impedance Z and theimpedance of the probe just before or after the self-test unit providedthe test impedance Z to the probe 903. Thus, for example, in oneembodiment, the sensor unit 902 is be provided to one end of theimpedance probe tape 2000 and the self-test unit 2602 is provided at anopposite end of the impedance probe tape 2000 to facilitate testing ofthe tape 2000 and/or to facilitate testing of the moisture sensor unit902.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrated embodiments and thatthe present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributed thereof, furthermore,various omissions, substitutions and changes may be made withoutdeparting from the spirit of the inventions. For example, althoughspecific embodiments are described in terms of the 900 MHz frequencyband, one of ordinary skill in the art will recognize that frequencybands above and below 900 MHz can be used as well. The wireless systemcan be configured to operate on one or more frequency bands, such as,for example, the HF band, the VHF band, the UHF band, the Microwaveband, the Millimeter wave band, etc. One of ordinary skill in the artwill further recognize that techniques other than spread spectrum canalso be used and/or can be used instead of spread spectrum. Themodulation use is not limited to any particular modulation method, suchthat modulation scheme used can be, for example, frequency modulation,phase modulation, amplitude modulation, combinations thereof, etc. Theforegoing description of the embodiments is, therefore, to be consideredin all respects as illustrative and not restrictive, with the scope ofthe invention being delineated by the appended claims and theirequivalents.

1. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said threshold is computed as an average of a plurality of sensor data values.
 2. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said threshold is computed at least in part as a weighted average of a plurality of sensor data values.
 3. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said severity is computed according to how far a sensor reading has risen above said threshold.
 4. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said severity is computed at least in part as a function of how far and how rapidly sensor readings have risen above said threshold value.
 5. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said severity is computed at least in part as a function of how many sensor readings have been measured above said threshold value.
 6. A moisture sensor system, comprising: a sensor unit comprising a moisture sensor provided to a moisture probe, said sensor unit configured to receive instructions, said sensor unit configured to report a severity of a moisture level when said sensor unit determines that data measured by said moisture sensor fails a threshold test, said sensor unit configured to adjust said threshold according to sensor reading taken during a specified time period, wherein said severity is computed as a function of what percentage of recent sensor readings have been measured above said threshold value.
 7. The system of claim 1, further comprising means for wirelessly transmitting data from said moisture sensor to a monitoring station.
 8. The system of claim 1, further comprising means for wirelessly transmitting resistance data to a monitoring station.
 9. The system of claim 1, further comprising means for receiving instructions to close a water shutoff valve.
 10. The system of claim 1, wherein said sensor unit is configured as a wireless sensor unit configured to report data measured by said moisture sensor when said wireless sensor determines that said moisture data fails a threshold test, said wireless sensor unit configured to operating in a low-power mode when not transmitting or receiving data.
 11. The system of claim 1, further comprising a self-test module.
 12. The system of claim 1, wherein said self-test module provides a resistor to said first and second conductors.
 13. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by telephone.
 14. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by cellular telephone.
 15. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by cellular text messaging.
 16. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by pager.
 17. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by Internet.
 18. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by email.
 19. The system of claim 1, further comprising a monitoring computer configured to attempt to contact a responsible party by Internet instant messaging.
 20. The system of claim 1, further comprising a monitoring computer is configured to provide plots of moisture levels.
 21. The system of claim 1, wherein said system is configured to receive an instruction to change a status reporting interval.
 22. The system of claim 1, wherein said system is configured to receive an instruction to change a sensor data reporting interval.
 23. The system of claim 1, wherein a monitoring computer is configured to monitor a status of said sensor unit.
 24. The moisture sensor system of claim 1, wherein said severity of a moisture level depends at least in part on a length of time said moisture sensor has detected moisture above a threshold level.
 25. The moisture sensor system of claim 1, wherein said severity of a moisture level depends at least in part on a rate of raise in said moisture level.
 26. The sensor system of claim 1, said moisture probe comprising: a first probe comprising a first conductor with a plurality of pins; a second probe comprising a second conductor with a plurality of pins; and a substrate provided to said first probe and said second probe, said moisture sensor configured to measure an impedance between said first probe and said second probe.
 27. The system of claim 26, wherein said impedance comprises a resistance.
 28. The system of claim 26, wherein said impedance comprises a reactance.
 29. The system of claim 26, wherein said first and second conductors are substantially linear.
 30. The system of claim 26, wherein said first and second conductors are substantially linear and attached to said substrate in a substantially parallel alignment.
 31. The system of claim 26, wherein a peel-and-stick adhesive is provided to said substrate.
 32. The system of claim 26, wherein an adhesive is provided to a back side of said substrate.
 33. The system of claim 26, wherein an adhesive is provided to a front side of said substrate and wherein said first and second conductors are provided to said front side of said substrate.
 34. The system of claim 26, wherein said sensor unit configured as a wireless sensor unit configured to report data measured by said moisture sensor when said wireless sensor determines that said moisture data fails a threshold test, said wireless sensor unit configured to operating in a low-power mode when not transmitting or receiving data.
 35. The system of claim 26, wherein said substrate comprises a baseboard molding.
 36. The system of claim 26, wherein said substrate comprises a wall molding. 